I have a Cannon Lide25 scanner which seems to do what I think you need.

I have not used this before, but I will try it out and see what happens.

Here goes then!

I have just placed into the scanner three separate photographs and after opening the Canoscan dialogue box and set it to (MULTI SCAN). It went into scanning which just looks a bit like normal, but when you get as far as the file where you’re scanned photographs show, they show up as different photos. Then onto the directory where you want the scanned photographs to be sent and they are all there with separate file numbers, just as if you had made three separate scans. You can of course scan as many as you like or as few as is required at the same time.

I also scanned a sheet with separate photographs that was a leaflet with printing on and it just turned out the whole sheet as one unit / photo. I think what makes the difference is the fact that you leave a gap in between each photo to be scanned that you want to turn out as separate files. If that makes sense

I hope this helps you. Regards Migwell